ORA-02429: cannot drop index used for enforcement of unique/primary key

ORA-02429: cannot drop index used for enforcement of unique/primary key
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---when I execute

SQL> drop index IND_ON_HALIM_TEST ; ----its reply

ORA-02429: cannot drop index used for enforcement of unique/primary key


If it is an unique index that enforces unique constraint
you cannot simply drop it



You have to drop unique constraint BY

alter table tablename drop constraint constraintname;



=================================================
Hands on Example
=================================================

SQL*Plus: Release 11.1.0.6.0 - Production on Wed Jun 30 16:21:01 2010

Copyright (c) 1982, 2007, Oracle. All rights reserved.

SQL> CONN STLBAS/STLBAS@JUNCLS
Connected.
SQL>
SQL>
SQL> DROP TABLE HALIM_TEST ;

Table dropped.

SQL>
SQL> CREATE TABLE halim_test (id number,name varchar2(30)) ;

Table created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (100,'Mr. Halim');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (100,'Mr Cadot');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (200,'Mr. Arif');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (300,'Mr. Akash');

1 row created.

SQL>
SQL> COMMIT;

Commit complete.

SQL>
SQL>
SQL> create index IND_ON_HALIM_TEST on halim_test(ID);

Index created.

SQL> ALTER TABLE halim_test ADD PRIMARY KEY (ID) NOVALIDATE ;

Table altered.

SQL>
SQL>
SQL>
SQL> DROP index IND_ON_HALIM_TEST ;
DROP index IND_ON_HALIM_TEST
*
ERROR at line 1:
ORA-02429: cannot drop index used for enforcement of unique/primary key

SQL>
SQL>
SQL>
SQL>
SQL> SELECT owner, constraint_name, constraint_type, table_name
2 FROM user_constraints
3 WHERE table_name = 'HALIM_TEST';

OWNER CONSTRAINT_NAME C TABLE_NAME
------------------------------ ------------------------------ - ----------------

STLBAS SYS_C0084077 P HALIM_TEST

SQL>
SQL>
SQL> alter table halim_test drop constraint SYS_C0084077 ;

Table altered.

SQL>
SQL>
SQL>
SQL>
SQL> SELECT index_name, index_type, table_owner, table_name, table_type,
2 uniqueness
3 FROM user_indexes
4 WHERE table_name = 'HALIM_TEST';

INDEX_NAME INDEX_TYPE TABLE_OWNER
TABLE_NAME TABLE_TYPE UNIQUENES
------------------------------ --------------------------- ---------------------
--------- ------------------------------ ----------- ---------
IND_ON_HALIM_TEST NORMAL STLBAS
HALIM_TEST TABLE NONUNIQUE

SQL>
SQL>
SQL> drop index IND_ON_HALIM_TEST;

Index dropped.

SQL>
SQL>
SQL>
SQL>